Widespread annual screening mammography has resulted in detection of greater percentages of breast cancers measuring 1 cm in diameter. The diagnosis of malignancy and determination of the prognostic factors are typically made by image guided needle biopsy. The treatment of breast cancers involves a number of possible alternatives, including surgical removal, radiation therapy, chemotherapy, thermotherapy and combinations thereof. Breast tumors are surgically removed generally together with sentinel/regional lymph nodes.
Conventional techniques of post-operative treatment of residual tumors following gross removal of tumors include sequential or simultaneous administration of radiation and chemotherapy. Originally, radiation therapy involved whole breast irradiation. More recently partial irradiation of the lumpectomy cavity places an inflatable balloon in the space where the cancer was surgically removed to irradiate the surrounding tissue using an Iridium seed at the center of the balloon. This procedure typically requires multiple rounds of irradiation such as 15 minutes exposure, twice a day over a five day period. This procedure is also known as brachytherapy and has become the preferred alternative to whole breast irradiation. The rationale for this treatment is based upon the observation that over 80% of breast cancer recurrences appear within a radius of one centimeter from the initial tumor border. Success rates (reduced incidence of recurrence) using brachytherapy in breast cancer are considered to be similar to those of whole breast irradiation.
Breast cancer is a common malignancy in the United States and elsewhere in the world. Widespread screening mammography has resulted in detection of smaller tumors, in turn leading to breast saving operation i.e. lumpectomy and irradiation. Of late, partial irradiation of the affected site delivered through a radium source placed at the center of a balloon in one week is replacing the whole breast external beam irradiation given in six weeks. Although this approach shortens the treatment time and encourages more women to seek breast saving operation, it is still burdensome for the patient to carry a balloon in the breast for a week receiving treatment twice a day. Furthermore, the cost of the breast irradiation therapy remains high; an item which is part of the burgeoning healthcare budget.
Since the initial successes of brachytherapy, various intraoperative therapeutic procedures now utilize the cavity formerly occupied by the bulk of the tumor for placement of an inflatable device for subsequent tumor therapy, often in a combined modality (radiation and/or chemotherapy and/or hyperthermia together).
Radiation sources, e.g. a radium seed may be placed inside a balloon which is implanted into a breast of a patient. The balloon stays in place during the treatment period, e.g. for 10-15 days. When a patient returns for each treatment session (generally daily) the radiation source is inserted into the balloon for a period of time, perhaps twice a day, until the treatment period ends. This is inconvenient for the patient, and has the attendant risks and costs of radiation. Expenses include special facilities, radiation source and technical support.
Heat in balloons has been used to control uterine bleeding but not to destroy transformed cells. The uterus muscular tissue is very different type of tissue than breast and has a different construction than the breast (fatty tissue). Pressures of around 150 mm Hg are employed before the balloon device is activated, although pressure is generally not reported nor are descriptions of pathological effects on tissue of heat delivered in this manner.